A time to digital converter, abbreviated as TDC, is a device for recognizing events and providing a representation of the time they occurred. The TDC can be used to measure an absolute time of an event or to measure a difference or delay between multiple events.
In many systems, such as communication systems, there are multiple paths that need to operate in time. Delays between the paths can degrade communication bandwidth, speed, and reliability. The TDC can be used to determine time delays for the multiple paths. Then, the time delays are used to make adjustments and improve performance of the system.
Typically, a TDC is implemented using gate delays. The analog technology is susceptible to variations such as process, voltage and temperature variations, referred to as PVT variations. These variations impact the operation of the circuitry and can lead to variations in measuring time or delays for multiple paths. Furthermore, these variations limit the resolution or accuracy of such TDCs.
What is needed is a more accurate TDC that is less susceptible to PVT variations and provides a higher resolution.